Why does my last five characters of exporting a PGP key differ? : pgppractice | Torhoo darknet markets
Well, I'm glad you asked!
TO THE ASCII ARMOR SPEC! -- RFC 4880. The ASCII ARMOR specification is given in Section 6.2:
Concatenating the following data creates ASCII Armor:
An Armor Header Line, appropriate for the type of data
Armor Headers
A blank (zero-length, or containing only whitespace) line
The ASCII-Armored data
An Armor Checksum
The Armor Tail, which depends on the Armor Header Line
So the last 5 characters (=TGyi and =/eDz) are a checksum of the armored data. Oddly Section 6.2 doesn't define the checksum format, but an older version of the spec, the 1995 Internet Draft for PGP, does:
The Armor Checksum is a 24-bit CRC converted to four bytes of radix-64 encoding, prepending an equal-sign (=) to the four-byte code.
Checksums are used in a number of other places is the RFC, always defined as two-octet sums modulo 65536:
Then a two-octet checksum is appended, which is equal to the sum of the preceding session key octets, not including the algorithm identifier, modulo 65536.
Source - http://rfc-editor.org/rfc/rfc4880#section-6.2
